My cassette is rattling on my freehub

[k...@braukaiser.com]

mechanical question here:

On Saturday's ride I noticed annoying rattling from the back of the bike. Upon closer inspection it was the two 3 cog blocks (biggest 3 and the middle 3)  rattling on the freehub. The cassette is 10sp XT and the hub is DT Swiss 350. The cassette is new but the hub is original.

When I took it apart today I noticed that the aluminum piece, which is holding together a block of 3 cogs has noticeable rotational play around the freehub. I'm not sure that this was there before and given the large surfaces that push against each other I find it hard to believe that I wore out the freehub or cassette. What usually happens is that the cogs come lose from the aluminum piece that holds them together. 

While the freehub body is a bit worn from the smaller cogs (which attach directly to the freehub) I'm now unclear if I do need a new freehub. 

Any suggestions from this group? 

My bike used to be more quiet, so something is different now.

Kai

[Chris Bussiere]

Pics?

Also, does the surface of the hub appear to be damaged?  Are there any teeth of the spline that are obviously damaged?

It's common for aluminum freehubs to suffer some damage where the teeth meet if you are very strong rider (which you are), so that's my first suspect.

After that I'd check to make sure that the freehub isn't missing anything... some freehubs use hardened-steel inserts to spread the load on the softer aluminum.  If one of these is missing, it could be your issue.

~CB

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[Gary Muntz]

Check that the top (smallest) of the gears in the cassette is correctly placed on the splines of the freehub. There is probably one wide spline and one narrow one, and the rest are medium. If misaligned, your symptom would happen even when the lockring is tight.

Best of luck,

- Gary

[jlela...@gmail.com]

Awfully tough to guess without taking it apart or having a look. 

If it's a new cassette often times it can be a simple mis-fitting when it was installed. Just a little extra space, or the locking ring/ small cogs weren't on just right... Then it loosens up under torque.

...NBD most of the time, but if you go out and wail on it like that you could definitely break the other things...

Good luck. Hope it's a light fix. DT makes great hubs and spline damage is fairly rare with the modular cassettes. 

[k...@braukaiser.com]

Yeah, I wish it was something that simple. Unfortunately there is noticeable play and a gap between freehub and cassette. Here are some pics:

The freehub is pretty beat up from the 1st XT cassette that had only one spider that connected the largest 2:

http://braukaiser.com/blog/wp-content/uploads/2016/06/20160627_173658.jpg

These pics show the gap between the cassette and the freehub. I pushed the cassette all the way to the right, so there is a gap on one side and no gap on the other:

http://braukaiser.com/blog/wp-content/uploads/2016/06/20160627_173748.jpg

http://braukaiser.com/blog/wp-content/uploads/2016/06/20160627_174251.jpg

Looking at the splines and the cassette I don’t see evidence of deformation. At least not to the extend needed to cause this much play. Maybe they had all that play from the beginning and it only really started to annoy me on a downhill that took more than 10 min :)

Kai

[jlela...@gmail.com]

Nice job on the pics.

From what I see you need a new freehub body and you'll probably be in good shape. That's a fairly aggressive amount of damage to the splines on the freehub. 

I work on a lot of bikes. Newer, older, in between, on any level between great and totally beat to shit. Freehubs like that generally still work fine right up until you try to fit the new cassette, or even put the old one back on. It won't sit right. 

...Besides: Its only a matter of rides until one of those bigger gears cuts right through the freehub and spins...

[jlela...@gmail.com]

Also, to ease your mind, that amount of space/play between the modular 3 cog piece and the freehub appears normal from my angle here at home. 

Those bigger cassette sections always have a seemingly-too-spacious amount of play compared to the individual gears. Probably just my imagination or an engineering concern that's beyond me.  Either way it looks like new freehub = go in terms of that space concern. 

Good luck.

On Jun 27, 2016, at 7:03 PM, k...@braukaiser.com wrote:

[Steve Foley]

I had a similar problem with an XT cassette and a Stan's alloy free hub body . Actually for me one of the pins on the cassette broke. The gouging on the free hub was pretty bad, so I replaced it with a steel body and I've had no problems since. Granted the steel is a little heavier, but it's robust.

[k...@braukaiser.com]

Thanks guys. I ordered a freehub replacement in addition to new derailleur, which also broke on that trip, and more.

Btw I used two paint can openers to grab the hub end cap from the inside to pull it off. There's some special tool, but I don't have it.

Regarding the broken derailleur. It got pulled into the spokes, as it happens to many of us. This got me thinking: why don't we use these plastic spoke guards? Is it just for estetics? I looks cleaner without. But it's not cheap when the derailleur gets into the spokes.

Kai

[jlela...@gmail.com]

Nice work. You may want to order a derailleur hanger while you're doing that job. Just the slightest bend can put off a 10 speed system and it's easier to do that all at once. 

Fist shaking for the cassette pie plate is universal. That's just how it is, man. :)

[k...@braukaiser.com]

FYI, the new freehub came yesterday. It has the same play in the cassette as the old one. Could it be that this play is normal and I get rid of it by tightening the lock-nut?

Kai

[Joseph Catale]

Hey Kai,

I know I needed to shim my friends dt 240 years ago, I don't know if that applies to the 350.  
https://www.google.com/search?q=shim+dt+swiss

-Joe